java 合并排序 java并排显示

一、功能说明

1、实现并列排名：1、1、3、4、4、6

二、实现逻辑

1、将数据封装到User对象中，操作对象进行并列排名处理

三、代码

1、新建User对象

public class User {

    private String name;
    private Integer age;
    private Integer index;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getIndex() {
        return index;
    }

    public void setIndex(Integer index) {
        this.index = index;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        User user = (User) o;
        return Objects.equals(name, user.name) && Objects.equals(age, user.age) && Objects.equals(index, user.index);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age, index);
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", index=" + index +
                '}';
    }

    public User() {
    }

    public User(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
}

2、Rank 代码

public class RankDemo {
    public static void main(String[] args) {
        List<User> list = new ArrayList<>();
        User user0 = new User("张0", 33);
        User user1 = new User("张1", 38);
        User user2 = new User("张2", 60);
        User user3 = new User("张3", 56);
        User user4 = new User("张4", 38);
        User user5 = new User("张5", 64);
        User user6 = new User("张6", 56);
        User user7 = new User("张7", 26);
        User user8 = new User("张8", 33);
        User user9 = new User("张9", 55);

        Collections.addAll(list, user0, user1, user2, user3, user4, user5, user6, user7, user8, user9);

        List<User> rankList = list.stream().sorted(Comparator.comparing(User::getAge)).collect(Collectors.toList());

        int count = 1;

        for (int i = 0; i < rankList.size(); i++) {
            if (i == 0) {
                rankList.get(0).setIndex(count);
                count++;
            } else {
                if (rankList.get(i).getAge().equals(rankList.get(i-1).getAge())){
                    rankList.get(i).setIndex(rankList.get(i-1).getIndex());
                    count++;
                }else {
                    rankList.get(i).setIndex(count);
                    count++;
                }
            }
        }
        for (User user : rankList) {
            System.out.println("user = " + user);
        }
    }
}

3、输出展示

Connected to the target VM, address: '127.0.0.1:53811', transport: 'socket'
user = User{name='张7', age=26, index=1}
user = User{name='张0', age=33, index=2}
user = User{name='张8', age=33, index=2}
user = User{name='张1', age=38, index=4}
user = User{name='张4', age=38, index=4}
user = User{name='张9', age=55, index=6}
user = User{name='张3', age=56, index=7}
user = User{name='张6', age=56, index=7}
user = User{name='张2', age=60, index=9}
user = User{name='张5', age=64, index=10}
Disconnected from the target VM, address: '127.0.0.1:53811', transport: 'socket'

Process finished with exit code 0